The present invention relates to oral compositions comprising plaque-inhibiting or plaque-removing enzymes and to a method for inhibiting plaque formation or removing plaque using such oral compositions.
Dental plaque is a mixture of bacteria, epithelial cells, leukocytes, macrophages and other oral exudates that forms on the surface of unclean teeth. The bacteria produce highly branched polysaccharides which together with microorganisms from the oral cavity form an adhesive matrix for the continued proliferation of plaque. Left untreated, the formation of dental plaque will eventually lead to dental caries, gingival inflammation, periodontal disease, and eventually tooth loss. As plaque continues to accumulate, rock-hard white or yellowish deposits arise. These deposits are called calcified plaque, calculus or tartar, and are formed in the saliva from plaque and minerals, in particular calcium.
Oral polysaccharides are produced from sucrose introduced into the mouth, e.g. as a food or beverage constituent, by the action of cariogenic microorganisms such as Streptococcus mutans or Streptococcus sanguis growing in the oral cavity. These oral polysaccharides comprise water-soluble dextran having primarily xcex1-1,6 glucosidic linkages, and a major component of water-insoluble extracellular polysaccharides called xe2x80x9cmutanxe2x80x9d comprised of a backbone with xcex1-1,3-glycosidic linkages and branches with xcex1-1,6-glycosidic linkages. Mutan binds to hydroxyapatite (constituting the hard outer porous layer of the teeth) and to acceptor proteins on the cell surface of said cariogenic bacteria adhering to the teeth surface.
Numerous attempts have been made to combat this process by either eliminating the plaque or by altering the environment by changing the composition of the plaque, and many toothpastes and other oral care compositions have, with varying success, aimed at removing or inhibiting plaque. The goal of effectively inhibiting plaque in particular has remained elusive, however, and the need remains for oral care compositions that in normal use are effective at inhibiting plaque formation and the accompanying dental diseases that can result from plaque formation.
WO 97/06775 discloses oral compositions comprising an oxidoreductase, and optionally a dextranase and/or a mutanase, for bleaching of teeth, but no plaque-inhibiting or plaque-removing effects of such compositions are described or suggested.
To prevent the formation of dental caries, plaque and tartar, it has been suggested to add a dextranase and/or a mutanase and/or other enzymes to oral care compositions and products.
JP patent publication 8012544 (Lion) describes a plaque preventing effect of dextranase, mutanase and triclosan and/or biosol.
U.S. Pat. No. 4,353,891 (Guggenheim et al.) concerns plaque removal using mutanase from Trichoderma harzianum CBS 243.71 to degrade mutan synthesized by cultivating Streptococcus mutans strain CBS 350.71 identifiable as OMZ 176. It is stated that the critical ingredient in dental plaque is a water-insoluble polysaccharide with xcex1-1,3-glucosidic bonds and that such polysaccharide material termed mutan is not attacked by dextranase.
Guggenheim et al. (1972), Caries Res. 6, p. 289-297, disclose that the extent of dental plaque of rats is not significantly affected by the simultaneous use of a dextranase and a 1,3-glucanase (mutanase).
Hare et al. (1978), Carbohydrate Research 66, p. 245-264, found that a synergistic effect is obtained when hydrolysing and solubilizing oral glucans with a bacterial dextranase in combination with bacterial xcex1-1,3 glucanase from Cladosporium resinae. 
U.S. Pat. No. 4,438,093 (The Research Foundation for Microbial diseases of Osaka) describes oral compositions comprising a dextranase and a xcex1-1,3-glucanase (mutanase), both being present in an amount of 0.5 to 100 enzyme units per gram of said oral composition, in an enzyme unit ratio of 1:2 to 2:1. Said dextranase is derived from a bacteria within the genus Corynbacterium and said xcex1-1,3-glucanase is derived from a bacteria within the genus Pseudomonas,
GB 2,206,585 (Dental Chem Co. Ltd.) describes a tooth-cleaning agent containing hydroxyapatite as a polishing agent, with a laevanase, dextranase and mutanase immobilized on the hydroxyapatite.
U.S. Pat. No. 5,145,665 (Henkel) discloses a composition for the care of the mouth and teeth comprising a dextranase and/or xcex1-1,3-glucanase for cleaving polysaccharides in the mouth.
FR 2,651,433 (DANA) concerns dentifrice products containing a dextranase to act on recent plaque, a mutanase to act on old and insoluble plaque, and a mixture of other enzymes having bactericidal action
U.S. Pat. No. 5,320,830 (Proctor and Gamble) describes toothpaste compositions for the reduction of plaque and gingivitis comprising a) a surfactant, b) an enzyme, c) a chelating agent d) a fluoride source, e) a silica abrasive and f) a carrier. The enzyme is an endoglucanase, papain, a dextranase and/or a mutanase.
It has now surprisingly been found that oral care compositions comprising one or more starch-hydrolysing or starch-modifying enzymes are effective for inhibiting/preventing dental plaque formation and/or for removing plaque.
The object of the present invention is thus to provide oral compositions that are effective for inhibiting/preventing plaque formation and for removing plaque, as well as a method for inhibiting plaque formation or for removing plaque.
A first aspect of the invention thus relates to an oral care composition comprising a plaque-inhibiting and/or plaque-removing effective amount of at least one starch-hydrolysing enzyme and/or at least one starch-modifying enzyme.
In a second aspect, the invention relates to a method for inhibiting plaque formation or removing plaque, comprising contacting the teeth and/or gums with an oral care composition comprising a plaque-inhibiting and/or plaque-removing effective amount of at least one starch-hydrolysing enzyme and/or at least one starch-modifying enzyme for a period of time to obtain a plaque-inhibiting or plaque-removing effect.